As a method of measuring a three-dimensional shape of an industrial product or the like, a focal method has been widely employed.
As a technology relating to measurement by the focal method, Patent Document 1 is known, for example. In a device disclosed in Patent Document 1, when measurement is to be made by the focal method, pattern light is projected to an object to be measured, and an image of this pattern is picked up by an image pickup system and observed so as to measure a focal position, whereby the shape of the object to be measured is measured.
[Patent Document 1] Japanese Patent No. 2928548